The 3rd Generation Partnership Project (3GPP) has discussed various technologies that can improve system throughput. It can be said that expanding frequencies to be used is the easiest way to improve system throughput. The 3GPP has reviewed the technology called Carrier Aggregation (CA) in Release 10 and Release 11. CA is a technology of bundling component carriers (CCs) having a bandwidth of 20 MHz to be used to improve system throughput and a data rate to its maximum. In order to employ this CA technology, frequency bands that can be used as CCs are necessary. For this reason, additional frequency bands that can be used in wireless communication of a cellular system have been demanded.
A technology of sharing a frequency band has been proposed as the technology for using an additional frequency band. Patent Literature 1, for example, discloses a technology of controlling transmission parameters of transmission devices of different networks in cooperation with the networks to increase the sum of capacities of all the networks. In addition, Patent Literature 2 discloses a technology of avoiding temporally continuous interference in a primary system (a television broadcasting system) when a dedicated frequency band or the like allocated to the primary system is used by another system in a contention method.